Study On The Occurrence Mechanism Of Rock Burst In Zhongnan Mountain Road Tunnel

Rock burst is one of the main disasters which effect the safe construction of road tunnel. Study on occurrence mechanism of rock bust is one of the key technology problems which effect the safe construction of tunnel. Research on the occurrence mechanism of rock bust has very important engineering value. Combining with the engineering practice of the extra-long road tunnel of zhongnan mountain and focus on the rock burst, this paper discusses the rock burst mechanism, prediction and prevention of the zhongnan mountain road tunnel.The geological condition of the qinling zhongnan mountain road tunnel is complicated, and rock burst is the main disaster. Based on the engineering geological conditions of qinling zhongnan mountain Extra-long road tunnel,this article has concluded several research results about the basic conception of rock burst and prediction, made a discussion about mechanical properties of rock burst and analyzed the failure characteristics and mechanism of the burst rock. This text suggests that either tensile splitting failure or shear failure occurred during the formation of the rock burst. It's tensional and shearing compound failure mechanism based on splitting failure. At the same time, after systematically analyzing the influencing factors of rock burst, the reasons leading to rock burst is considered very complex. It concerned about many factors such as land stress situations, bottom lithology, buried depth, rock-mass structures, groundwater, the size and the shape of excavation section, excavation method and so on. The land stress conditions and bottom layer lithology are decisive factor to the rock burst producing and other factors cannot be ignored.Through the analysis of ground stress in study area, lithology conditions, rock mass structures, geological structure combining with the researching of tests of rock mechanics about rock burst, considered that number 2 ventilation shafts and air duct system of the Qinling Tunnel Zhongnan has reached the middle ~ higher stress conditions which meet the rock burst stress conditions, it may occurred Minor ~ moderate rock burst surrounding the construction in IV and V surrounding rock. It predicted the major rock burst lot and proposed the prevent measures.